1. Field of the Invention
The present invention pertains to silver catalysts suitable for the manufacture of ethylene oxide by the partial oxidation of ethylene in the gas phase. More particularly, the present invention pertains to silver catalysts supported on a macroporous ceramic support in which the silver particle size is related to the macropore size.
2. Description of the Related Art
Supported silver catalysts for use in the partial oxidation of ethylene in the gas phase such that the average diameter of the silver particles is less than a fixed fraction of the number-average pore diameter of the support are known (see for example EP-A 0 172 565 and EP-A 0 428 845). The silver catalysts of the prior art display high selectivity (at high activity) and favorable ageing behavior, characteristics which determine the economics of the manufacture of ethylene oxide. In view of the increased competition between ethylene oxide producers there is yet a need for an improved silver catalyst having even greater selectivity (at high activity) and/or more favorable ageing behavior, and thus improved economics for ethylene oxide manufacture.